Manufacturing method and process of polytetrafluoroethylene
Aug 19, 2022
Summary of molding methods for PTFE products
1. Molding method
2. Push method
3. Skin bag method
4. Spraying method
5. Weaving
6. Winding method
7. Rolling method
8. Extrusion method
9. Bonding method
10. Welding method
11. Heat setting method
12. Machining method
PTFE sintering process
Molding shrinkage: 3.1-5.0%
Molding temperature: 330-380℃
Sintering conditions: the best temperature should not exceed 385 degrees, otherwise the molecules will be necrotic and affect the quality.
Material properties
Long-term use temperature of -200--260 degrees, excellent chemical corrosion resistance, corrosion resistance to all chemicals, the lowest friction coefficient among plastics, PTFE weather resistance and good electrical properties, its electrical insulation Sex is not affected by temperature, and it is known as the "Plastic King".
1. It is transparent or translucent, the higher the crystallinity, the worse the transparency. The raw materials are mostly powdery resins or concentrated dispersions, which have extremely high molecular weight and are thermoplastic polymers with high crystallinity.
2. Suitable for making corrosion-resistant parts, anti-wear parts, seals, insulating parts and medical equipment parts 1 K)
Formability
1. Crystalline material, low moisture absorption.
2. Poor fluidity, easy to decompose, and produces corrosive gas during decomposition. The molding temperature should be strictly controlled, the mold should be heated, and the gating system should have a small resistance to the material flow of PTFE pipes.
3. Powder resin is often formed by powder powder metallurgy and sintering method. The sintering temperature is 360-375 degrees, and can not exceed 410 degrees. Emulsion resins are usually processed by cold extrusion and sintering, which can form an anti-corrosion layer on the surface of the article. If the transparency and toughness of the product are required, rapid cooling should be adopted. Extrusion molding can also be adopted, and pipes, rods and profiles can be extruded.
4. The melt viscosity of PTFE is very high, and the volume viscosity decreases with the increase of shear stress, showing the characteristics of its non-Newtonian fluid.
5. Secondary processing, can be hot-pressed, welded, bonded, strengthened, mechanically processed, etc. to obtain the final product.
6. It is best to use the first step of curve sintering to dry at 120 degrees
The second step is to carry out temperature treatment at 250 degrees such as filled graphite or two-fluidized ink.
3. The third step is processed once at 345 degrees
4. The fourth step is to process at 375 degrees
5. The fifth step is not to cool down too fast
